The present invention relates to novel 6-keto- .omega.-aryl-PGE.sub.1 compounds which are useful agents for the induction of prostacyclin-like pharmacological effects. Accordingly, these compounds are useful for pharmacological purposes for which prostacyclin and related substances are employed. The essential material constituting disclosure of the preparation and use of these novel compounds is incorporated here by reference from Ser. No. 829,679, filed Sept. 2, 1977.